Dental device for obtaining the centric relation of the jaws



Oct. 23, 1962 G. c. REYNOLDS 3,059,335

DENTAL DEVICE FOR OBTAINING THE CENTRIC RELATION OF THE JAWS Filed April 6, 1960 2 Sheets-Sheet l I pa l3 59 2O 4 WA. \11. 37 4| SEEK gi 7 26 H 2 v '2 27 l @120 3 4 2 ga 6 H 1 *J 75- 55 61 INVENTOR 2 A'l'l' o RNEY Oct. 23,

G. C. REYNOLDS bENTAL DEVICE FOR OBTAINING THE CENTRIC RELATION OF THE JAWS Filed April 6, 1960 5 %4 as 35 FIG. 8

2 Sheets-Sheet 2 FIG. 7

INVENTOR BY W 4 iv/ y ATTORNEY United States Patent C) 3,059,335 DENTAL DEVICE FOR OBTAINING THE CENTRIC RELATION OF THE JAWS Grover C. Reynolds, 4401 Charlotte Ave., Nashville, Tenn. Filed Apr. 6, 1960, Ser. No. 20,495 Claims. (CI. 32-19) This invention relates to a dental device for obtaining the centric relation of the jaws, and more particularly to such a device which may be universally adjustable.

In the conventional method of making a set of false teeth for a patient, impressions of the persons gums are made in soft plastic material such as wax. A harder stone-like material in molten form is poured into the molds of the gums formed by the impressions and permitted to set to form a stone-like reproduction or model of the edentulous gums. Another pink plastic material, such as wax, is pressed over the gum surfaces of the stone-like models for both the upper and the lower jaws to form upper and lower base plates. A flat metal supporting plate is then placed against the outer surface of each base plate opposite the gum surface in such a manner that the metal plates oppose each other in spaced relation. The upper metal plate has a depending stylus, While the lower metal plate has a thin layer of wax spread over a small surface directly beneath the stylus. The plastic base plates and the supporting metal plates are removed from their respective models and inserted into the mouth of the patient and the gums inserted into the cavities or impressions of the plastic base plates. The patient closes his mouth and chews, moving his lower jaw laterally and back and forth to permit the stylus to trace a configuration in the waxed surface on the lower metal plate. In all patients, the stylus describes a substantially V-shaped path, known as a Gothic Arch.

The plastic base plates and the metal plates are then removed from the patients mouth and the models are replaced in the impressions of the base plates. With the stylus held in the apex of the Gothic Arch and adjusted to proper elevation, the models are secured to an articulator by means of plaster of Paris. In this crude manner, the centric relation of the jaws and gums are obtained preliminary to the making of a set of false teeth for the patient. The term centric relation refers to the natural relationship of an upper jaw and a lower jaw of a patient when the jaws are normally closed. By nature, the centric relation of any persons jaws is not symmetrical, nor is it identical to the centric relation of any other persons jaws.

It is therefore an object of this invention to provide a pair of support plates for plastic dental base plates, which support plates may be universally adjusted with respect to each other, while in the patients mouth, and locked in the adjusted position of the plates in. order to obtain the true centric relation of the patients jaws.

Another object of this invention is to provide a pair of flat plates for supporting plastic dental base plates containing impressions of the upper and lower gums, and means for giving the support plates relative three-dimensional translatory movement and pivotal movement about lateral and longitudinal axes.

Another object of this invention is to provide a pair of support plates for plastic dental base plates, the support plates being easily connected and disconnected to each other and provided with means for locking the plates in substantially any universally adjusted position.

Further objects and advantages of this invention will be apparent from the following description, taken in conjunction with the drawings, wherein:

FIG. 1 is a front elevational view of the invention, with the plates pivoted to open position;

Patented Oct. 23, 1962 FIG. 2 is a side elevational view similar to FIG. 1, with the plates in an intermediate pivoted position;

FIG. 3 is a view similar to FIG. 2 with the plates in closed position;

FIG. 4 is a section taken along the line 4-4 of FIG. 3;

FIG. 5 is a section taken along the line -55 of FIG. 3;

FIG. 6 is a section taken along the line 66 of FIG. 3, disclosing the upper support plate, transverse bar and pivotal links in various operative positions;

FIG. 7 is a section taken along the line 77 of FIG. 3;

FIG. 8 is a section taken along the line 8-8 of FIG. 7.

Referring now to the drawings in more detail, and particularly to FIGS. 1-3, the upper plastic base plate 10 is for-med around the stone-like model 11 of the upper gum of the patient and secured to the upper surface of an upper flat metal support plate 12. Holes 13 are provided in the upper support plate 12 to permit the plastic material or wax of the base plate 10 to filter through the holes 13 and maintain a more secure bond between the base plate 10 and the support plate 12. In a like manner, a lower plastic base plate 14 forming an impression of the lower gum on the lower stone-like model 15, is secured to a lower flat metal support plate 16 by means of holes 17 in the plate 16.

The upper support plate 12 is provided with depending parallel flanges 20 and 21 on opposite sides thereof, each flange having a longitudinal slot '22 and 23, respectively. Also mounted on the upper support plate 12 toward the front of and along its longitudinal axis is a cylindrical stylus 24 adapted tobe adjusted in a direction normal to the plane of the plate 12. The adjustment of the stylus is effected by teeth 25 spaced longitudinally along the surface of the stylus 24 adapted to mesh with a gear 26 supported on the end of a shaft 27 rotatably mounted in bearing 28 fixed to the bottom of support plate 12. The other end of the shaft 27 is adapted to be manually rotated by means of a knurled disc or knob 2'9. Adapted to lock the stylus 24 in any adjusted vertical position is a set screw 30 threadedly supported in the bearing 28.

Adapted to connect the upper support plate 12 and the lower support plate 16 is a transverse bar 33 comprising a pair of telescoping members 34 and 35. Although member 34 is disclosed as having a channel-shaped crosssectionand the telescoping member 35 is disclosed as an angle or L-shaped member, the members 34 and 35 may have any convenient cross section provided they are adapted to slide longitudinally of each other. The inside tclescoping member 34 is provided with a cylindrical extension or hinge pin 36 having a threaded end adapted to extend through the flange 20 in sliding and pivotal engagement with the slot 22. The threaded extension 36 is secured in place by the nut 37. In a like manner a threaded cylindrical extension or hinge pin 38 is fixed to the opposite end of the outside telescoping member 35 and adapted to extend through the flange 21 in sliding and pivotal engagement with the slot 23. The threaded extension 38 is secured in place by means of the nut 39. It is to be understood that the means of pivotally and slidingly connecting the telescoping members 34 and 35 to the respective flanges 20 and 21 is not necessarily limited to the details of construction of the extensions and nuts 36-39.

Each of the telescoping members 34 and 35 have registering longitudinal slots 40 and 41, respectively. Although FIGS. 1, 6, 7, and 8 disclose the telescoping members 34 and 35 in fully extended position, the member 34 may be telescoped within the member 35 to withdraw the extensions 36 and 38 from their respective slots 22 and 23, after the nuts 37 and 39 have been removed. In order to telescope the members 34 and 35, a rotary gear 45 extends transversely through the slots 40 and 41 and is adapted to engage an upper rack 46 formed in the slot 41 of the member 35, and formed to the right of the .gum surfaces of the models 11 gear 45, when the transverse bar 33 is in extended position, as disclosed in FIGS. 6 and 7. Likewise, a lower rack 47 is formed in the slot 40 in the inner telescoping member 34 to the left of the gear 45 when the transverse bar 33 is in extended position. The gear 45 is provided with flanges 4S and 45 at opposite ends to hold the gear 45 within the respective slots 49 and 41 and is provided with a slotted head 59 to permit rotation of the gear 4-5 by insertion of a screwdriver. Thus, by rotating the slotted head 50 and gear 45 in a counterclockwise direction, as disclosed in FIG. 7, the members 34 and 35 will be telescoped to withdraw the extensions 36 and 33 from their respective slots 22 and 23 in order to disconnect the transverse bar 33 from the upper support plate 12.

A pair of upstanding cars 53 and 54 are formed along the rear edge and near the opposite sides of the lower support plate 16. A link 55 is pivoted at its lower end to the ear 53 by means of a pin 56. In like manner, another link 57 is pivoted at its lower end to the ear 54 by means of a pin 58. A threaded bolt 59 extends through the upper end of the link '5 and the registering slots 49 and 41 and is threadedly secured on the rear surface of the bar 33 by means of a nut 68. A similar threaded bolt 61 extends through the upper end of the link 57 and the registering slots 40 and 41 and is threadedly secured on the rear surface of the transverse bar 33 by means of a nut 62. Both bolts 59 and 61 are adapted to permit the upper ends of the links 55 and 57 to independently slide longitudinally or pivot within the registering slots 40 and 41 in the transverse bar 33.

Located on the upper surface of the lower support plate 16 and adapted to register with the lower end of the stylus 24 is a layer of wax 65. When the plates 12 and 16 are closed, as disclosed in FIG. 3, and the device is inserted into a patients mouth, the movement of the jaws will cause the stylus 24 to form a Gothic Arch 66 in the wax 65. In order to lock thestylus 24- at the apex of the Gothic Arch 66, a longitudinally slidable guide plate 67 having a V-shaped notch 68 at the rear end thereof is mounted on top of the lower support plate 16. In order to effect the longitudinal sliding movement, the guide plate 67 has a longitudinal slot 69 adapted to slid- .ably reecive pins 70 fixed in the lower plate 16 and having upper threaded ends to receive locking nuts 71. Thus,

the guide plate 67 may be longitudinally adjusted to lock and unlock the stylus 24 at the apex of the Gothic Arch 66, as best disclosed in FIG. 5, by engaging the V-sh'aped notch 68 against the stylus 24.

The operation of the invention is as follows:

After the models of the gums 11 and 15 have been poured and set and the impressions removed, wax or other plastic material is heated and pressed over the and 15 to form the plastic base plates and 14. With the upper and lower support vplates 12 and 16 assembled, the transverse bar 33 expanded, the threaded extensions 36 and 38 registering with their respective slots 22 and 23 and the nuts 37 and 39 securing the extensions in place, the warm, soft plastic base plates 10 and 14 are placed on their respective metal support plates 12 and 16 and permitted to solidify in the holes 13 and 17. Although the nuts 37 and 38 are threaded over their respective extensions 36 and 38, they are sufficiently loose to permit the extensions to slide longitudinally within their respective slots 22 and 23 and also to permit the upper plate 12 to pivot about the extensions 36 and 38. Moreover, the nuts 60 and 62 are also loosened to permit the sliding and pivotal movement of the bolts 59 and 61, respectively, within the registering slots 40 and 41. In this loosened condition, the models 11 and are removed from their respective base plates 10 and 14, and the entire metal plate assembly with the base plates 10 and 14 are placed within the patients mouth so that the patients gums will fit within the cavities of the base plates 10 and 14. By loosening the set screw and turning the disc or knob 29, the stylus 24 resting on the wax layer 65 is adjusted to elevate the upper plate 12 so that the mouth, jaws and lips are in proper vertical relation. The nuts 71 are loosened and the guide plate 67 is moved forward to the dashed line position of FIG. 5 so that it will not interfere with the movement of the stylus 24. The patient is then requested to chew so that the stylus 24 will form the Gothic Arch 66 in the wax layer 65. When the patient has stopped chewing, the stylus 24 is located in the apex of the Gothic Arch 66 and the guide plate 67 is moved toward the rear until the apex of the V-shaped notch 68 abuts the stylus 24, and the nuts 71 are tightened to lock the guide plate 67 and the stylus 24 in place, as disclosed in FIG. 5.

With the stylus 24 locked in position, the nuts 37, 39, 60 and 62 are tightened to lock the metal plates 12 and 16 in their fixed adjusted relative position. The entire assembly is then removed from the mouth of the patient, the models 11 and 15 reinserted into the cavities of the base plates 10 and 14, and the models 11 and 15 are attached to a conventional articulator 75 by means of plaster of Paris 76 and 77. By this means the jaws and gums of the patient are properly simulated in true centric relation, and by removing the entire plate assembly and the base plates 10 and 14, the artificial teeth may be made on the gum models 11 and 15 for the patient in true centric relation.

As will be observed in FIG. 1, all the adjustments for the metal plate assembly, the gear head 50, the bolt heads 59 .and 61, the stylus knob 29, the locking set screw 30, and the nuts 71, are available from the front of the device. Consequently, the support plates 12 and 16 may be introduced into or withdrawn separately from the patients mouth, and the plates 12 and 16 may be connected or disconnected and locked in place or unlocked While in the patients mouth. Whether or not the paltes 12 and 16 are locked in place within the patients mouth and then withdrawn as a unit or withdrawn separately and then reassembled, they will be attached to the articulator with the same degree of accuracy, which is greater than that of any conventional mechanisms now employed for obtaining the centric relation of the jaws.

To withdraw the plates 12 and 16 separately after the patient has finished chewing, the head 50 is turned until the extensions 36 and 38 are withdrawn from their respective flange slots 22 and 23 and the ends of the telescoping members 34 and 35 opposite their respective extension ends abut against the depending flanges 21 and 20, respectively. The nuts 37 and 39 may be removed entirely before the plates are inserted in the mouth or the nuts may be loosened before the plates are inserted and removed after the patient has finished chewing. The bolt heads 59 and 61 are then tightened to lock the bar 33 and sup pont plate 16 rigidly in spaced relation. By sliding the flanges 20 and 21 over the abutting ends of the telescoping members 35 and 34, respectively, the upper support plate 12 may be separately removed from the patients mouth, and subsequently the locked bar 33 and lower plate 16 may be removed. To reassemble the device, the ends of the telescoping members 34 and 35 are slipped into abutting relation with their respective flanges 21 and 20 until the stylus 24 again registers with the apex of the Gothic Arch 66.

It will he noted that the upper and lower support plates 12 and 16 may be adjusted in three dimensional translatory relative positions as well as in relative pivotal positions about a pair of horizontal axes normal to each other. Thus, the entire assembly permits practically any type of universal adjustment between the upper plate '12 and the lower plate v16 in order to obtain the true centric relation of the patients jaws.

It will be apparent to those skilled in the art that various changes may be made in the invention, without departing from the spirit and scope thereof, and therefore the invention is notlimited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. An adjustable dental device for obtaining the centric relation of the jaws comprising an upper plate for receiving an impression of the upper gum and a lower plate for receiving an impression of the lower gum, each of said plates having a longitudinal axis and a transverse axis, a transverse bar comprising a pair of members having registering first elongated slots and adapted to telescope transversely of said lower plate, each of said members having a transverse hinge pin extending from one end thereof and on the opposite end from said other member, a flange depending from each side of said upper plate and having a second slot extending longitudinally of said upper plate, said second slots being in transverse alignment, said hinge pins being adapted to extend through said opposite second slots in pivotal and longitudinally slidable engagement therewith, means for contracting and expanding said telescoping members relative to each other to respectively disengage and engage said hinge pins with their respective second slots, a pair of links having their lower ends pivoted about axes longitudinally of said lower plate, a pivot pin at the upper end of each link independently slidably and pivotally engaging the registering first slots of said telescoping members, means for locking said pivot pins in said first slots and means for locking said hinge pins in their respective second slots.

2. The invention according to claim 1 in which the means for expanding and contracting said transverse members comprises a first rack along one edge of one of said first slots and a second rack along the opposite edge of said other first slot, a rotary gear engaging said first and second racks, and means for rotating said gear in said racks for telescoping said members.

3. The invention according to claim 2 in which a stylus is mounted for axial movement normal to said upper plate, means for axially moving said stylus and means for looking said stylus in any axial adjusted position.

4. The invention according to claim 3 in which spaced teeth are formed axially of said stylus and said means for moving said stylus comprises a rotary gear engaging said teeth.

5. The invention according to claim 3 in which a guide plate is mounted on said lower plate for slidable longitudinal movement thereon, the longitudinal axes of said guide plate and said stylus being substantially coplanar.

References Qited in the file of this patent UNITED STATES PATENTS 716,781 Stocks Dec. 23, 1902 1,718,868 Meadows June 25, 1929 1,791,796 Christopher Feb. 10, 1931 2,003,692 Meadows June 4, 1935 2,792,629 Green May 21, 1957 2,869,414 Brant Nov. 18, 1958 

